There is an art to effectively stopping a bicycle in an emergency. Doing it
incorrectly could cause you to: 1) hit the object you are trying to avoid;
2) somersault over the handlebars; 3) lose control of the bike as the rear
wheel skids out from under you. If you are like many people, you instinctively
grab both brakes in an emergency and apply them equally until the bike begins
to skid. This is inefficient because you have no control over a locked wheel
(it cannot be steered), and a wheel that is skidding offers you virtually no
stopping power.
When you apply either the front or rear brake, the bicycle begins to slow down
and your weight transfers forward because of inertia. The more weight a wheel
supports, the more effective the applied braking force, and the less tendency
to skid.
Thus, if you apply only the rear brake hard, your weight is shifted to the front,
decreasing weight on the rear wheel. since the rear wheel is supporting less weight,
it will skid as you brake, decreasing the effectiveness of the brake.
Applying only the front brake hard also shifts weight to the front wheel. In this
case, however, the weight transfer increases the effectiveness of the brake, and
the tendency of the braked front wheel to skid is greatly reduced. However, the
danger is that if the front brake is applied too hard, the rear wheel will lift
off the road and the rider may be pitched over the handlebars.
The implications, the, for effective braking are as follows:
- Braking with the rear brake alone will avoid pitchover, but it is not very effective.
- The theoretically fastest stop is made with the front brake alone, but this is
dangerous-only a slight error will pitch you over.
- The best system for a fast, safe stop is to use both brakes in a 3:1 ratio, front:rear,
which produces the optimum deceleration. If the rear wheel starts to skid, this
indicates that you are unweighting the rear wheel almost to the pitchover point.
Therefore, when the rear wheel skids, ease up slightly on the front brake.
- When braking hard, slide your body back in the saddle as far as possible. Although
it is not necessary for an effective panic stop, you can transfer even more weight
to the rear wheel by lifting your buttocks off the saddle and thrusting them straight
back over the rear axle.
- If you are carrying a heavy load on the rear of your bike, you will be able to brake harder before pitchover occurs.
Reprinted from "Effective CyclingTM Notebook"
from the League of American Bicyclists.
For more information about the League of American Bicyclists, visit
their web site, www.bikeleague.org,
or e-mail them at bikeleague@aol.com.
